1. Field of the Invention
The present invention is in the field of incandescent lamps. More particularly, the present invention is in the field of incandescent lamps or light bulbs which are used in conjunction with night vision equipment.
2. Brief Description of the Prior Art
Night vision equipment used for military or like purposes electronically enhances infra red (ir) radiation to form images which are viewed by military or like personnel. Frequently, if not most commonly, personnel who use night vision equipment are occupying vehicles or aircraft. However, normal or regular incandescent light bulbs utilized for illuminating instrument panels or the like of vehicles and aircraft are not compatible with the use of night vision equipment. This is because normal or regular incandescent light bulbs emit substantial radiation in the infra red range. Consequently, if the infra red output of ordinary instrument panel light bulbs were amplified by the night vision equipment an image of such brightness would be produced which would be likely to cause eye injury to the personnel using the night vision equipment. Infra red radiation output of ordinary incandescent light bulbs used in the instrument panels of vehicles and aircraft, could also be detected by the night vision equipment of an adversary. The prior art has attempted to solve the foregoing problems in applications requiring the use of night vision equipment by interposing a filter between the light bulb and the personnel so as to substantially filter out the light of undesirable wave length of the ordinary incandescent light bulbs of instrument panels and the like. The filter of the prior art is located externally to the light bulb, and as such it forms an additional component or part of the equipment which must be obtained and installed into the vehicle or aircraft. The present invention provides a better solution to the foregoing problems.